STOP AND CHANGE I wasn't particularly interested in environmental issues when I was at school or university - to be honest, I was thinking about other things, like most people.

I've been doing this for 40 years, for my sins. I joined the (British) Green Party in the mid-1970s, and did 10 years with the party, then 10 years with Friends of the Earth, and most of my campaigning in those days was trying to stop people doing things: stop polluting, stop destroying the natural world, it was all about "stop" and very little about doing things, making things work brilliantly well. It wasn't until I went to the Earth Summit in 1992, in Rio de Janeiro, Brazil, that I thought, "Actually, there are countless people who want to make [the sustainability] story work, people in business who want to make it work, religious leaders." I came back from it and thought, "OK, I'm going to spend the rest of my life advocating differently, by talking about positive energy, solutions not problems, opportunities not threats, innovation as the key driver of change. And that's what we do at (Porritt's NGO) Forum for the Future.

I have been coming over to Hong Kong to work with Swire Group for more than 10 years; we've been doing advisory work, particularly with the property division, on some of their long-term plans for sustainable buildings, green building technology, energy efficiency.

CHINA CHALLENGE When I was chairman of the Sustainable Development Commission in the UK for nine years (2000-2009), it had a role to work with China, India and Mexico, to help promote climate-change remedial action and sustainable development. I visited China four times, but I am not a China expert. I read a lot about China because, I say to friends, if we can't find a way to make China sustainable, we're not going to be able to make the world sustainable. It's as simple as that. I'm positive about China for two reasons. One, China needs to make dramatic changes to the way it manages the natural environment. The protests in Beijing earlier this year at the extremely severe pollution are a sign of things to come and the Chinese government is obviously focused on stability. If one of the reasons why people are becoming less content with their situation is poor environmental quality, then the government will get it sorted. The second, rather more interesting, reason is that China has recognised there is a huge global market for environmental goods and services. They are very ambitious to get a larger and larger share of that market.

FUTURE SHOCKS I am not trying to put myself forward as a kind of soothsayer. My story (Porritt's latest book is titled The World We Made: Alex McKay's Story from 2050) is trying to show people what is possible and then say, if it is possible, "Why don't we try to make it happen?" It is true that the changes we have to go through are immense; changes in agriculture, land use, waste management, energy, water technologies. We have to get all this moving really fast, within the next 15 years. I honestly don't think it's unrealistic (but it) will depend on a lot of changes in our political system; it means confronting people who are blocking progress and finding ways of either working around them or bringing them into a different kind of wealth creation. There will be shocks to the system. In The World We Made, there's a global famine in 2025 and there are huge climate shocks as a consequence of not having done enough about it up until now. We'll have real problems with terrorism, as you would expect. So these shocks to the system are what jolt politicians out of today's relative inertia into saying, "OK. Got it. We're going to have to do something about it." Without those shocks, I think politicians would just carry on tinkering at the edges.

PRINCELY PASSION (Britain's) Prince Charles has been a real leader. When I started advising him, he'd occasionally say, "Well you're quite new to this game, Jonathon." His interest in the natural world goes back a long way - to his childhood, really. The Prince of Wales has worked incredibly hard with world leaders to create financial instruments that allow rich countries to help emerging countries recover some of the economic value of their forests. He's not your normal Prince of Wales, not that I have ever known any other. It makes me very cross when I see how the very cynical media in the UK like to make fun of his efforts, but he never stops working at the sustainability agenda. As far as I'm concerned, the world is a better place with leaders like that and we need more of them.

GREEN ZONING Everything we know about urban living tells us you have to keep your green spaces, you have to maintain these special areas where people can get access to the natural world. They act as green lungs, they provide a retreat from industrial civilisation and the built environment. We need them for biodiversity reasons, for water purification reasons. Hong Kong's (country parks have) a very important role to play in terms of water quality and managing the water regime. I'm not here to advise the Hong Kong government; all I know is that successful cities in the future will cherish their green areas.

TIME TICKING It's quite a problem dealing with sustainability if you're not a scientist - and I can say that because I am not a scientist and I have had to work unbelievably hard to overcome my lack of scientific training. (The West) ends up with a lot of politicians who, and I'm being charitable here, are not well informed about critical scientific debates and tend to make less-good decisions because they are not understanding the issues. In my wilder moments, I have two compulsory re-education programmes that I'd like to implement - one would be to re-educate politicians, so they would be able to understand science and technology and engineering, and I'd like to re-educate economists, so they understood what the real world was. Economists are just as problematic and dangerous as politicians. They wouldn't know the real world if it jumped up and hit them in the face.

The question we all have to go on asking is, are we going to take advantage of the time we've got? Will we genuinely learn how to live sustainably on this planet? This is what they call an existential question; that is, a question that affects the well-being of the entire human species. You can't get bigger than that.


Jonathon Porritt's new book, The World We Made: Alex McKay's Story from 2050 , is in bookshops now.